# MySQL Connector/Python - MySQL driver written in Python.
# Copyright (c) 2009,2010, Oracle and/or its affiliates. All rights reserved.
# Use is subject to license terms. (See COPYING)

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation.
# 
# There are special exceptions to the terms and conditions of the GNU
# General Public License as it is applied to this software. View the
# full text of the exception in file EXCEPTIONS-CLIENT in the directory
# of this software distribution or see the FOSS License Exception at
# www.mysql.com.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

"""Various MySQL constants and character sets
"""

from .errors import ProgrammingError

def flag_is_set(flag, flags):
    """Checks if the flag is set
    
    Returns boolean"""
    if (flags & flag) > 0:
        return True
    return False
    
class _constants(object):
    
    prefix = ''
    desc = {}
    
    def __new__(cls):
        raise TypeError("Can not instanciate from %s" % cls.__name__)
        
    @classmethod
    def get_desc(cls,name):
        try:
            return cls.desc[name][1]
        except:
            return None

    @classmethod
    def get_info(cls,n):
        try:
            res = {}
            for v in cls.desc.items():
                res[v[1][0]] = v[0]
            return res[n]
        except:
            return None
    
    @classmethod
    def get_full_info(cls):
        res = ()
        try:
            res = ["%s : %s" % (k,v[1]) for k,v in list(cls.desc.items())]
        except Exception as e:
            res = ('No information found in constant class.%s' % e)
        
        return res

class _constantflags(_constants):

    @classmethod
    def get_bit_info(cls, v):
        """Get the name of all bits set

        Returns a list of strings."""
        res = []
        for name,d in cls.desc.items():
            if v & d[0]:
                res.append(name)
        return res
        
class FieldType(_constants):
    
    prefix = 'FIELD_TYPE_'
    DECIMAL     = 0x00
    TINY        = 0x01
    SHORT       = 0x02
    LONG        = 0x03
    FLOAT       = 0x04
    DOUBLE      = 0x05
    NULL        = 0x06
    TIMESTAMP   = 0x07
    LONGLONG    = 0x08
    INT24       = 0x09
    DATE        = 0x0a
    TIME        = 0x0b
    DATETIME    = 0x0c
    YEAR        = 0x0d
    NEWDATE     = 0x0e
    VARCHAR     = 0x0f
    BIT         = 0x10
    NEWDECIMAL  = 0xf6
    ENUM        = 0xf7
    SET         = 0xf8
    TINY_BLOB   = 0xf9
    MEDIUM_BLOB = 0xfa
    LONG_BLOB   = 0xfb
    BLOB        = 0xfc
    VAR_STRING  = 0xfd
    STRING      = 0xfe
    GEOMETRY    = 0xff
    
    desc = {
        'DECIMAL':       (0x00, 'DECIMAL'),
        'TINY':          (0x01, 'TINY'),
        'SHORT':         (0x02, 'SHORT'),
        'LONG':          (0x03, 'LONG'),
        'FLOAT':         (0x04, 'FLOAT'),
        'DOUBLE':        (0x05, 'DOUBLE'),
        'NULL':          (0x06, 'NULL'),
        'TIMESTAMP':     (0x07, 'TIMESTAMP'),
        'LONGLONG':      (0x08, 'LONGLONG'),
        'INT24':         (0x09, 'INT24'),
        'DATE':          (0x0a, 'DATE'),
        'TIME':          (0x0b, 'TIME'),
        'DATETIME':      (0x0c, 'DATETIME'),
        'YEAR':          (0x0d, 'YEAR'),
        'NEWDATE':       (0x0e, 'NEWDATE'),
        'VARCHAR':       (0x0f, 'VARCHAR'),
        'BIT':           (0x10, 'BIT'),
        'NEWDECIMAL':    (0xf6, 'NEWDECIMAL'),
        'ENUM':          (0xf7, 'ENUM'),
        'SET':           (0xf8, 'SET'),
        'TINY_BLOB':     (0xf9, 'TINY_BLOB'),
        'MEDIUM_BLOB':   (0xfa, 'MEDIUM_BLOB'),
        'LONG_BLOB':     (0xfb, 'LONG_BLOB'),
        'BLOB':          (0xfc, 'BLOB'),
        'VAR_STRING':    (0xfd, 'VAR_STRING'),
        'STRING':        (0xfe, 'STRING'),
        'GEOMETRY':      (0xff, 'GEOMETRY'),
    }
    
    @classmethod
    def get_string_types(cls):
        return [
            cls.VARCHAR,
            cls.ENUM,
            cls.VAR_STRING, cls.STRING,
            ]
    
    @classmethod
    def get_binary_types(cls):
        return [
            cls.TINY_BLOB, cls.MEDIUM_BLOB,
            cls.LONG_BLOB, cls.BLOB,
            ]
    
    @classmethod
    def get_number_types(cls):
        return [
            cls.DECIMAL, cls.NEWDECIMAL,
            cls.TINY, cls.SHORT, cls.LONG,
            cls.FLOAT, cls.DOUBLE,
            cls.LONGLONG, cls.INT24,
            cls.BIT,
            cls.YEAR,
            ]
    
    @classmethod
    def get_timestamp_types(cls):
        return [
            cls.DATETIME, cls.TIMESTAMP,
            ]

class FieldFlag(_constantflags):
    """
    Field flags as found in MySQL sources mysql-src/include/mysql_com.h
    """
    _prefix = ''
    NOT_NULL             = 1 <<  0
    PRI_KEY              = 1 <<  1
    UNIQUE_KEY           = 1 <<  2
    MULTIPLE_KEY         = 1 <<  3
    BLOB                 = 1 <<  4
    UNSIGNED             = 1 <<  5
    ZEROFILL             = 1 <<  6
    BINARY               = 1 <<  7

    ENUM                 = 1 <<  8
    AUTO_INCREMENT       = 1 <<  9
    TIMESTAMP            = 1 << 10
    SET                  = 1 << 11

    NO_DEFAULT_VALUE     = 1 << 12
    ON_UPDATE_NOW        = 1 << 13
    NUM                  = 1 << 14
    PART_KEY             = 1 << 15
    GROUP                = 1 << 14    # SAME AS NUM !!!!!!!????
    UNIQUE               = 1 << 16
    BINCMP               = 1 << 17

    GET_FIXED_FIELDS     = 1 << 18
    FIELD_IN_PART_FUNC   = 1 << 19
    FIELD_IN_ADD_INDEX   = 1 << 20
    FIELD_IS_RENAMED     = 1 << 21

    desc = {
        'NOT_NULL':             (1 <<  0, "Field can't be NULL"),
        'PRI_KEY':              (1 <<  1, "Field is part of a primary key"),
        'UNIQUE_KEY':           (1 <<  2, "Field is part of a unique key"),
        'MULTIPLE_KEY':         (1 <<  3, "Field is part of a key"),
        'BLOB':                 (1 <<  4, "Field is a blob"),
        'UNSIGNED':             (1 <<  5, "Field is unsigned"),
        'ZEROFILL':             (1 <<  6, "Field is zerofill"),
        'BINARY':               (1 <<  7, "Field is binary  "),
        'ENUM':                 (1 <<  8, "field is an enum"),
        'AUTO_INCREMENT':       (1 <<  9, "field is a autoincrement field"),
        'TIMESTAMP':            (1 << 10, "Field is a timestamp"),
        'SET':                  (1 << 11, "field is a set"),
        'NO_DEFAULT_VALUE':     (1 << 12, "Field doesn't have default value"),
        'ON_UPDATE_NOW':        (1 << 13, "Field is set to NOW on UPDATE"),
        'NUM':                  (1 << 14, "Field is num (for clients)"),

        'PART_KEY':             (1 << 15, "Intern; Part of some key"),
        'GROUP':                (1 << 14, "Intern: Group field"),   # Same as NUM
        'UNIQUE':               (1 << 16, "Intern: Used by sql_yacc"),
        'BINCMP':               (1 << 17, "Intern: Used by sql_yacc"),
        'GET_FIXED_FIELDS':     (1 << 18, "Used to get fields in item tree"),
        'FIELD_IN_PART_FUNC':   (1 << 19, "Field part of partition func"),
        'FIELD_IN_ADD_INDEX':        (1 << 20, "Intern: Field used in ADD INDEX"),
        'FIELD_IS_RENAMED':          (1 << 21, "Intern: Field is being renamed"),
    }

class ServerCmd(_constants):
    _prefix = 'COM_'
    SLEEP           =  0
    QUIT            =  1
    INIT_DB         =  2 
    QUERY           =  3
    FIELD_LIST      =  4
    CREATE_DB       =  5
    DROP_DB         =  6
    REFRESH         =  7
    SHUTDOWN        =  8
    STATISTICS      =  9
    PROCESS_INFO    = 10
    CONNECT         = 11
    PROCESS_KILL    = 12
    DEBUG           = 13
    PING            = 14
    TIME            = 15
    DELAYED_INSERT  = 16
    CHANGE_USER     = 17
    BINLOG_DUMP     = 18
    TABLE_DUMP      = 19
    CONNECT_OUT     = 20
    REGISTER_SLAVE  = 21
    STMT_PREPARE    = 22
    STMT_EXECUTE    = 23
    STMT_SEND_LONG_DATA = 24
    STMT_CLOSE      = 25
    STMT_RESET      = 26
    SET_OPTION      = 27
    STMT_FETCH      = 28
    DAEMON          = 29

class ClientFlag(_constantflags):
    """
    Client Options as found in the MySQL sources mysql-src/include/mysql_com.h
    """
    LONG_PASSWD             = 1 << 0
    FOUND_ROWS              = 1 << 1
    LONG_FLAG               = 1 << 2
    CONNECT_WITH_DB         = 1 << 3
    NO_SCHEMA               = 1 << 4
    COMPRESS                = 1 << 5
    ODBC                    = 1 << 6
    LOCAL_FILES             = 1 << 7
    IGNORE_SPACE            = 1 << 8
    PROTOCOL_41             = 1 << 9
    INTERACTIVE             = 1 << 10
    SSL                     = 1 << 11
    IGNORE_SIGPIPE          = 1 << 12
    TRANSACTIONS            = 1 << 13
    RESERVED                = 1 << 14
    SECURE_CONNECTION       = 1 << 15
    MULTI_STATEMENTS        = 1 << 16
    MULTI_RESULTS           = 1 << 17
    SSL_VERIFY_SERVER_CERT  = 1 << 30
    REMEMBER_OPTIONS        = 1 << 31
    
    desc = {
        'LONG_PASSWD':        (1 <<  0, 'New more secure passwords'),
        'FOUND_ROWS':         (1 <<  1, 'Found instead of affected rows'),
        'LONG_FLAG':          (1 <<  2, 'Get all column flags'),
        'CONNECT_WITH_DB':    (1 <<  3, 'One can specify db on connect'),
        'NO_SCHEMA':          (1 <<  4, "Don't allow database.table.column"),
        'COMPRESS':           (1 <<  5, 'Can use compression protocol'),
        'ODBC':               (1 <<  6, 'ODBC client'),
        'LOCAL_FILES':        (1 <<  7, 'Can use LOAD DATA LOCAL'),
        'IGNORE_SPACE':       (1 <<  8, "Ignore spaces before ''"),
        'PROTOCOL_41':        (1 <<  9, 'New 4.1 protocol'),
        'INTERACTIVE':        (1 << 10, 'This is an interactive client'),
        'SSL':                (1 << 11, 'Switch to SSL after handshake'),
        'IGNORE_SIGPIPE':     (1 << 12, 'IGNORE sigpipes'),
        'TRANSACTIONS':       (1 << 13, 'Client knows about transactions'),
        'RESERVED':           (1 << 14, 'Old flag for 4.1 protocol'),
        'SECURE_CONNECTION':  (1 << 15, 'New 4.1 authentication'),
        'MULTI_STATEMENTS':   (1 << 16, 'Enable/disable multi-stmt support'),
        'MULTI_RESULTS':      (1 << 17, 'Enable/disable multi-results'),
        'SSL_VERIFY_SERVER_CERT':     (1 << 30, ''),
        'REMEMBER_OPTIONS':           (1 << 31, ''),
    }
    
    default = [
        LONG_PASSWD,
        LONG_FLAG,
        CONNECT_WITH_DB,
        PROTOCOL_41,
        TRANSACTIONS,
        SECURE_CONNECTION,
        MULTI_STATEMENTS,
        MULTI_RESULTS,
    ]

    @classmethod
    def get_default(cls):
        flags = 0
        for f in cls.default:
            flags |= f
        return flags

class ServerFlag(_constantflags):
    """
    Server flags as found in the MySQL sources mysql-src/include/mysql_com.h
    """
    _prefix = 'SERVER_'
    STATUS_IN_TRANS             = 1 << 0
    STATUS_AUTOCOMMIT           = 1 << 1
    MORE_RESULTS_EXISTS         = 1 << 3
    QUERY_NO_GOOD_INDEX_USED    = 1 << 4
    QUERY_NO_INDEX_USED         = 1 << 5
    STATUS_CURSOR_EXISTS        = 1 << 6
    STATUS_LAST_ROW_SENT        = 1 << 7
    STATUS_DB_DROPPED           = 1 << 8
    STATUS_NO_BACKSLASH_ESCAPES = 1 << 9

    desc = {
        'SERVER_STATUS_IN_TRANS':            (1 << 0, 'Transaction has started'),
        'SERVER_STATUS_AUTOCOMMIT':          (1 << 1, 'Server in auto_commit mode'),
        'SERVER_MORE_RESULTS_EXISTS':        (1 << 3, 'Multi query - next query exists'),
        'SERVER_QUERY_NO_GOOD_INDEX_USED':   (1 << 4, ''),
        'SERVER_QUERY_NO_INDEX_USED':        (1 << 5, ''),
        'SERVER_STATUS_CURSOR_EXISTS':       (1 << 6, ''),
        'SERVER_STATUS_LAST_ROW_SENT':       (1 << 7, ''),
        'SERVER_STATUS_DB_DROPPED':          (1 << 8, 'A database was dropped'),
        'SERVER_STATUS_NO_BACKSLASH_ESCAPES':   (1 << 9, ''),
    }

class RefreshOption(_constants):
    """Options used when sending the COM_REFRESH server command."""
    
    _prefix = 'REFRESH_'
    GRANT = 1 << 0
    LOG = 1 << 1
    TABLES = 1 << 2
    HOST = 1 << 3
    STATUS = 1 << 4
    THREADS = 1 << 5
    SLAVE = 1 << 6
    
    desc = {
        'GRANT': (1 << 0, 'Refresh grant tables'),
        'LOG': (1 << 1, 'Start on new log file'),
        'TABLES': (1 << 2, 'close all tables'),
        'HOSTS': (1 << 3, 'Flush host cache'),
        'STATUS': (1 << 4, 'Flush status variables'),
        'THREADS': (1 << 5, 'Flush thread cache'),
        'SLAVE': (1 << 6, 'Reset master info and restart slave thread'),
    }
    
class CharacterSet(_constants):
    """MySQL supported character sets and collations
    
    List of character sets with their collations supported by MySQL. This
    maps to the character set we get from the server within the handshake
    packet.
    
    The list is hardcode so we avoid a database query when getting the
    name of the used character set or collation.
    """
    
    desc = [
      None,
      ("big5","big5_chinese_ci",True), # 1
      ("latin2","latin2_czech_cs",False), # 2
      ("dec8","dec8_swedish_ci",True), # 3
      ("cp850","cp850_general_ci",True), # 4
      ("latin1","latin1_german1_ci",False), # 5
      ("hp8","hp8_english_ci",True), # 6
      ("koi8r","koi8r_general_ci",True), # 7
      ("latin1","latin1_swedish_ci",True), # 8
      ("latin2","latin2_general_ci",True), # 9
      ("swe7","swe7_swedish_ci",True), # 10
      ("ascii","ascii_general_ci",True), # 11
      ("ujis","ujis_japanese_ci",True), # 12
      ("sjis","sjis_japanese_ci",True), # 13
      ("cp1251","cp1251_bulgarian_ci",False), # 14
      ("latin1","latin1_danish_ci",False), # 15
      ("hebrew","hebrew_general_ci",True), # 16
      None,
      ("tis620","tis620_thai_ci",True), # 18
      ("euckr","euckr_korean_ci",True), # 19
      ("latin7","latin7_estonian_cs",False), # 20
      ("latin2","latin2_hungarian_ci",False), # 21
      ("koi8u","koi8u_general_ci",True), # 22
      ("cp1251","cp1251_ukrainian_ci",False), # 23
      ("gb2312","gb2312_chinese_ci",True), # 24
      ("greek","greek_general_ci",True), # 25
      ("cp1250","cp1250_general_ci",True), # 26
      ("latin2","latin2_croatian_ci",False), # 27
      ("gbk","gbk_chinese_ci",True), # 28
      ("cp1257","cp1257_lithuanian_ci",False), # 29
      ("latin5","latin5_turkish_ci",True), # 30
      ("latin1","latin1_german2_ci",False), # 31
      ("armscii8","armscii8_general_ci",True), # 32
      ("utf8","utf8_general_ci",True), # 33
      ("cp1250","cp1250_czech_cs",False), # 34
      ("ucs2","ucs2_general_ci",True), # 35
      ("cp866","cp866_general_ci",True), # 36
      ("keybcs2","keybcs2_general_ci",True), # 37
      ("macce","macce_general_ci",True), # 38
      ("macroman","macroman_general_ci",True), # 39
      ("cp852","cp852_general_ci",True), # 40
      ("latin7","latin7_general_ci",True), # 41
      ("latin7","latin7_general_cs",False), # 42
      ("macce","macce_bin",False), # 43
      ("cp1250","cp1250_croatian_ci",False), # 44
      None,
      None,
      ("latin1","latin1_bin",False), # 47
      ("latin1","latin1_general_ci",False), # 48
      ("latin1","latin1_general_cs",False), # 49
      ("cp1251","cp1251_bin",False), # 50
      ("cp1251","cp1251_general_ci",True), # 51
      ("cp1251","cp1251_general_cs",False), # 52
      ("macroman","macroman_bin",False), # 53
      None,
      None,
      None,
      ("cp1256","cp1256_general_ci",True), # 57
      ("cp1257","cp1257_bin",False), # 58
      ("cp1257","cp1257_general_ci",True), # 59
      None,
      None,
      None,
      ("binary","binary",True), # 63
      ("armscii8","armscii8_bin",False), # 64
      ("ascii","ascii_bin",False), # 65
      ("cp1250","cp1250_bin",False), # 66
      ("cp1256","cp1256_bin",False), # 67
      ("cp866","cp866_bin",False), # 68
      ("dec8","dec8_bin",False), # 69
      ("greek","greek_bin",False), # 70
      ("hebrew","hebrew_bin",False), # 71
      ("hp8","hp8_bin",False), # 72
      ("keybcs2","keybcs2_bin",False), # 73
      ("koi8r","koi8r_bin",False), # 74
      ("koi8u","koi8u_bin",False), # 75
      None,
      ("latin2","latin2_bin",False), # 77
      ("latin5","latin5_bin",False), # 78
      ("latin7","latin7_bin",False), # 79
      ("cp850","cp850_bin",False), # 80
      ("cp852","cp852_bin",False), # 81
      ("swe7","swe7_bin",False), # 82
      ("utf8","utf8_bin",False), # 83
      ("big5","big5_bin",False), # 84
      ("euckr","euckr_bin",False), # 85
      ("gb2312","gb2312_bin",False), # 86
      ("gbk","gbk_bin",False), # 87
      ("sjis","sjis_bin",False), # 88
      ("tis620","tis620_bin",False), # 89
      ("ucs2","ucs2_bin",False), # 90
      ("ujis","ujis_bin",False), # 91
      ("geostd8","geostd8_general_ci",True), # 92
      ("geostd8","geostd8_bin",False), # 93
      ("latin1","latin1_spanish_ci",False), # 94
      ("cp932","cp932_japanese_ci",True), # 95
      ("cp932","cp932_bin",False), # 96
      ("eucjpms","eucjpms_japanese_ci",True), # 97
      ("eucjpms","eucjpms_bin",False), # 98
      ("cp1250","cp1250_polish_ci",False), # 99
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      ("ucs2","ucs2_unicode_ci",False), # 128
      ("ucs2","ucs2_icelandic_ci",False), # 129
      ("ucs2","ucs2_latvian_ci",False), # 130
      ("ucs2","ucs2_romanian_ci",False), # 131
      ("ucs2","ucs2_slovenian_ci",False), # 132
      ("ucs2","ucs2_polish_ci",False), # 133
      ("ucs2","ucs2_estonian_ci",False), # 134
      ("ucs2","ucs2_spanish_ci",False), # 135
      ("ucs2","ucs2_swedish_ci",False), # 136
      ("ucs2","ucs2_turkish_ci",False), # 137
      ("ucs2","ucs2_czech_ci",False), # 138
      ("ucs2","ucs2_danish_ci",False), # 139
      ("ucs2","ucs2_lithuanian_ci",False), # 140
      ("ucs2","ucs2_slovak_ci",False), # 141
      ("ucs2","ucs2_spanish2_ci",False), # 142
      ("ucs2","ucs2_roman_ci",False), # 143
      ("ucs2","ucs2_persian_ci",False), # 144
      ("ucs2","ucs2_esperanto_ci",False), # 145
      ("ucs2","ucs2_hungarian_ci",False), # 146
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      None,
      ("utf8","utf8_unicode_ci",False), # 192
      ("utf8","utf8_icelandic_ci",False), # 193
      ("utf8","utf8_latvian_ci",False), # 194
      ("utf8","utf8_romanian_ci",False), # 195
      ("utf8","utf8_slovenian_ci",False), # 196
      ("utf8","utf8_polish_ci",False), # 197
      ("utf8","utf8_estonian_ci",False), # 198
      ("utf8","utf8_spanish_ci",False), # 199
      ("utf8","utf8_swedish_ci",False), # 200
      ("utf8","utf8_turkish_ci",False), # 201
      ("utf8","utf8_czech_ci",False), # 202
      ("utf8","utf8_danish_ci",False), # 203
      ("utf8","utf8_lithuanian_ci",False), # 204
      ("utf8","utf8_slovak_ci",False), # 205
      ("utf8","utf8_spanish2_ci",False), # 206
      ("utf8","utf8_roman_ci",False), # 207
      ("utf8","utf8_persian_ci",False), # 208
      ("utf8","utf8_esperanto_ci",False), # 209
      ("utf8","utf8_hungarian_ci",False), # 210
    ]
    
    @classmethod
    def get_info(cls,setid):
        """Retrieves character set information as tuple using an ID
        
        Retrieves character set and collation information based on the
        given MySQL ID.

        Returns a tuple.
        """
        try:
            r = cls.desc[setid]
            if r is None:
                raise
            return r[0:2]
        except:
            raise ProgrammingError("Character set '%d' unsupported" % (setid))

    @classmethod
    def get_desc(cls,setid):
        """Retrieves character set information as string using an ID
        
        Retrieves character set and collation information based on the
        given MySQL ID.

        Returns a tuple.
        """
        try:
            return "%s/%s" % cls.get_info(setid)
        except:
            raise
    
    @classmethod
    def get_default_collation(cls, charset):
      """Retrieves the default collation for given character set

      Raises ProgrammingError when character set is not supported.

      Returns a string.
      """

      for cid, c in enumerate(cls.desc):
        if c is None:
          continue
        if c[0] == charset and c[2] is True:
          return c[1], c[0], cid

      raise ProgrammingError("Character set '%s' unsupported." % (charset))
    
    @classmethod
    def get_charset_info(cls, name, collation=None):
        """Retrieves character set information as tuple using a name
        
        Retrieves character set and collation information based on the
        given a valid name.
        
        Raises ProgrammingError when character set is not supported.

        Returns a tuple.
        """
        idx = None
        
        if collation is None:
          collation, charset, idx = cls.get_default_collation(name)
        else:
          for cid, c in enumerate(cls.desc):
            if c is None:
              continue
            if c[0] == name and c[1] == collation:
              idx = cid
              break
              
        if idx is not None:
          return (idx,) + (name,collation)
        else:
          raise ProgrammingError("Character set '%s' unsupported." % (name))

    @classmethod
    def get_supported(cls):
        """Retrieves a list with names of all supproted character sets

        Returns a tuple.
        """
        res = []
        for info in cls.desc:
            if info and info[0] not in res:
                res.append(info[0])
        return tuple(res)

    
